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| KMR Kahale & Martin Racing |
| Neo/FC Notes |
This is a project I entered with some reluctance.
The Yellow car was moving along just fine and setting
once in a life time performance marks. It's only real
limitation as far as I could see was the fact that tire size
was restricted by body width and the ability to get the
chassis any narrower than it already was. A limit that
still persist today.
Following the advice that "we've been there and
done that and this works better" line of thought I
finally gave in to building the current car based on the
old platform as closely as possible. Continuity being
the idea. Build on what I knew.
The basic premises is that a longer wheelbase car
is a more efficient car at getting what power you have
to the ground. There would be no real way of knowing
unless I built it, collected the required data and
processed that data to a conclusion. "Game on", as
they say.
In the above graph is the history of both cars. At
point 21 the beginning of the Neo/FC platform. Point 11
is the Yellow Vette at the beginning of the 25/25 motor
runs and all points before the use of other winds in
progressively hotter steps.
The rather ragged performance of the new car is
magnified by the use of 5 different motor layouts
instead of the one from points 11 to 21. One knocked
out magnet that did in a block and an arm accounting
for half of the changes. No excuses here, just
explanation of events as they happened.
It took twice as many outings to get the new car to
the same place as the old car due to those changes and
collect enough data to make a meaningful comparison.
In a rambling fashion here is what I've learned or
observed so far. It took three outings to get the Yellow
car from it's .539 starting point with the 25/25 to it's end
point .499. It took six outings, two chassis and four
motor configurations to get from a .502 starting point to
the current best of .443. We added 7 MPH to the old car
and lost 7 MPH in the new car for the same result. We
improved the Yellow car about 4/10 and the new car
about 6/10. In that respect the new car is a bit more
successful. We've gone further.
Breaking down the number however we see a
different story. The premise was that the longer car
would be a more efficient conveyor of power. Once the
Yellow car was sorted it was a bracket car logging .499
to .506 passes on several outings. The new car is more
of a shotgun with a range of .443 to low 5's. In fact the
average of all outings to date is .491 or .008 better than
the old car. Dismal.
Power to weight ratio goes to the new car by 8%.
Power to the track goes to the old car by 4%. New car
makes 15% more power but weighs 8% more. Old car
was still gaining outing after outing and the new
car...not so much.
The good news comes from points 11 to 29
spanning both cars. The progress is still steady and
pretty much on a linear track. We've gone from .540 to
.440 which is a big jump over the ET's considered.
.425 is the target. A number I believe is competitive
even at todays low 4 best pace.
There are some hurdles to clear and they all fight
each other directionally. 54 motors can be some very
nice workhorses that get it done but lack the power to
be top half of the field performers. 43's make the power
to get it done, place top half but lack the stamina
needed to make the required number of passes. They
are braid hogs as well, high maintenance and
temperamental. I'll leave split winds to those with way
more knowlege.
Bite is going to get to be more critical as supplies
of traction additives dry up with no one stepping up
(factory) to fill the void. It's already a headache.
The hardest is balancing bite to power type. Not
power level but power type. Until there is some
consistency in the glue ups, (glue proper and control of
track temperature) we are shooting at moving targets
with chance more in control than skill of the outcomes.
Arm diameter, wind, gap, total flux are all in the dark.
I've had motors with enough grunt to pull high .05
short times pushing 15 pinions on 1.07+ tires. Building
torque is not an issue. Building enough torque with
enough RPM is. It requires winds that pull more amps
than the braid is happy with or most tracks can supply.
You can open the gap and play with the timing to get
more RPM but less torque. It requires even hotter winds
that are less efficient to keep the bottom pegged at a
target torque number while stretching the rpm limit.
Current thinking in tire widths and glue up has the
bottom number on short times pinned in the upper mid
.05 range. Improvement in ET thus must come from the
mid range (timing adjustment) balanced against the hit
torque (gap adjustment). Give the track some heat and
we are already outside any window of current thinking.
This car is pinned by braid performance. The cures
all run counter to effective power to weight ratios at this
point. At this point meaning current aero/power/bite
thus...something has to change to get the next big bite
at the apple.
point 21 the beginning of the Neo/FC platform. Point 11
is the Yellow Vette at the beginning of the 25/25 motor
runs and all points before the use of other winds in
progressively hotter steps.
The rather ragged performance of the new car is
magnified by the use of 5 different motor layouts
instead of the one from points 11 to 21. One knocked
out magnet that did in a block and an arm accounting
for half of the changes. No excuses here, just
explanation of events as they happened.
It took twice as many outings to get the new car to
the same place as the old car due to those changes and
collect enough data to make a meaningful comparison.
In a rambling fashion here is what I've learned or
observed so far. It took three outings to get the Yellow
car from it's .539 starting point with the 25/25 to it's end
point .499. It took six outings, two chassis and four
motor configurations to get from a .502 starting point to
the current best of .443. We added 7 MPH to the old car
and lost 7 MPH in the new car for the same result. We
improved the Yellow car about 4/10 and the new car
about 6/10. In that respect the new car is a bit more
successful. We've gone further.
Breaking down the number however we see a
different story. The premise was that the longer car
would be a more efficient conveyor of power. Once the
Yellow car was sorted it was a bracket car logging .499
to .506 passes on several outings. The new car is more
of a shotgun with a range of .443 to low 5's. In fact the
average of all outings to date is .491 or .008 better than
the old car. Dismal.
Power to weight ratio goes to the new car by 8%.
Power to the track goes to the old car by 4%. New car
makes 15% more power but weighs 8% more. Old car
was still gaining outing after outing and the new
car...not so much.
The good news comes from points 11 to 29
spanning both cars. The progress is still steady and
pretty much on a linear track. We've gone from .540 to
.440 which is a big jump over the ET's considered.
.425 is the target. A number I believe is competitive
even at todays low 4 best pace.
There are some hurdles to clear and they all fight
each other directionally. 54 motors can be some very
nice workhorses that get it done but lack the power to
be top half of the field performers. 43's make the power
to get it done, place top half but lack the stamina
needed to make the required number of passes. They
are braid hogs as well, high maintenance and
temperamental. I'll leave split winds to those with way
more knowlege.
Bite is going to get to be more critical as supplies
of traction additives dry up with no one stepping up
(factory) to fill the void. It's already a headache.
The hardest is balancing bite to power type. Not
power level but power type. Until there is some
consistency in the glue ups, (glue proper and control of
track temperature) we are shooting at moving targets
with chance more in control than skill of the outcomes.
Arm diameter, wind, gap, total flux are all in the dark.
I've had motors with enough grunt to pull high .05
short times pushing 15 pinions on 1.07+ tires. Building
torque is not an issue. Building enough torque with
enough RPM is. It requires winds that pull more amps
than the braid is happy with or most tracks can supply.
You can open the gap and play with the timing to get
more RPM but less torque. It requires even hotter winds
that are less efficient to keep the bottom pegged at a
target torque number while stretching the rpm limit.
Current thinking in tire widths and glue up has the
bottom number on short times pinned in the upper mid
.05 range. Improvement in ET thus must come from the
mid range (timing adjustment) balanced against the hit
torque (gap adjustment). Give the track some heat and
we are already outside any window of current thinking.
This car is pinned by braid performance. The cures
all run counter to effective power to weight ratios at this
point. At this point meaning current aero/power/bite
thus...something has to change to get the next big bite
at the apple.